In a recent study, researchers found the use of angiotensin converting enzyme inhibitor drugs (ACEIs) to lower blood pressure is linked to a high risk of lung cancer.
The cancer risk is higher compared with the use of another group of blood pressure drugs called angiotensin receptor blockers (ARBs).
The risk is particularly elevated among people using ACEIs for more than five years.
Although the risk for individual patients is modest, ACEIs are widely prescribed, so these small relative effects could translate into large absolute numbers of patients at risk for lung cancer.
The study was done by McGill University.
ACEIs are effective drugs used to treat high blood pressure.
Previous evidence suggests that ACEIs may increase the risk of lung cancer through the build-up of protein-like chemicals called bradykinin and substance P in the lung.
These chemicals have been found on a lung cancer tissue, and bradykinin may directly stimulate the growth of lung cancer.
However, previous observational studies examining this association are few and they report inconsistent results.
To better understand this possible association, the researchers analyzed UK primary care records for nearly one million patients who started taking a new antihypertensive drug between 1995 and 2015.
Patients were at least 18 years of age, with no previous cancer, and were followed up for an average of 6.4 years, during which time 7,952 cases of lung cancer were identified (a rate of 1.3 per 1000 person-years).
The team found that use of ACEIs was associated with an overall 14% increased risk of lung cancer compared with ARBs.
Links were found after five years of use and increased with longer durations of use, particularly in patients who used ACEIs for more than 10 years (31% increased risk).
Although the magnitudes of the observed estimates are modest, the researchers point out that ACEIs are one of the most widely prescribed drug classes.
As such, they say these findings should be replicated in other settings, particularly among patients exposed for longer durations.
This is an observational study, so no firm conclusions can be drawn about cause and effect.
The researchers cannot rule out the possibility that other unmeasured factors, such as socioeconomic differences, diet, and family history of lung cancer, may have affected the results.
However, this is the largest study to assess this specific association, and findings remained consistent after further analyses to test the strength of the results.
As such, the researchers conclude that the use of ACEIs is linked to an increased risk of lung cancer, and they call for additional studies, with long-term follow-up, to investigate the effects of these drugs on the incidence of lung cancer.
The study is published in The BMJ.
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Source: The BMJ.